Slack-adjuster.



H. F. SHAW.

SLACK ADJUSTER.

(Application filed Oct. 12, 1899.)

(No Model.)

Patented Feb. 6, I900.

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FFIQE.

SLACK-ADJUSTER.

SPECIFICATION forming part of Letters Patent No. 643,011, dated February 6, 1900.

Application filed October 12, 1899. Serial No. 733,436. (No model.)

To all whom it may concern:

Be it known that I, HENRY F. SHAW, a citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented an Improvement in Slack-Adj usters for Brake-Shoes of Railway- 7 Car Trucks, of which the following is a specification.

The object of my invention is to provide a cheap, simple, and durable self-operating or automatic slack-adjuster for brake-shoes of railway-car trucks, whereby the movement of the dead-lever actuates the double pawls so as to renew the relative positions of the brakeshoes in relation to the peripheries of the wheels of the car-trucks when worn away by frictional contact therewith through the action of stopping a train by means of the usual brake mechanism employed for the purpose and now in common use; and it consists in the construction, combination, and arrangement of double pawl and ratchet actuated by the movement of the dead-lever in connection therewith.

To the drawings which form a part of this specification reference is made.

Figure 1 represents a vertical sectional elevation showing a car-truck having an automatic slack adjuster applied thereto constructed to embody my invention. Fig. 2 represents a top plan showing a portion of the truck-frame with the slack-adjuster attached. Fig. 3 represents a detached view showing the upper end portion of the dead-lever with the pivoted pawls and vertical connecting-bar loosely pivoted to the shorter ends of the pawls.

A A represent the truck-frame, constructed with the wheels B B, brake-shoes C O, and

brake-beams D D, suspended from the opposite ends of the truck-frame by the fiat springretainers E E, as usual.

F represents the live-lever. To the upper end thereof is pivoted one end of the horizontal brake-rod G, the opposite end of which is pivoted to the floating lever, (not shown,) as heretofore constructed for the purpose.

H represents the horizontal tie-rod, one end of which is pivoted to the lower end of the live-lever F, the opposite end being pivoted to the lower end of the dead-lever K, as usual, The lower end portion of the said dead-lever K is pivoted to the brake-beam D, and the lower end portion of the live-lever F is pivoted to the opposite end brake-beam D or in the usual manner employed.

Now in order to carry out my invention in use I construct a double segmental ratchet which consists, essentially, of two upper parallel segmental ratchets L, provided on their upward edges with coarse or large teethsN, and two lower parallel segmental ratchets L, having smaller teeth M on their upward edges, and each segmental ratchet having a .com mon center, as shown, and having their outward ends united, or otherwise, and firmly bolted to the end of the truck-frame A, their opposite ends being united, so as to give strength and rigidity, and are formed on an incline downward, as shown. Now it will be seen that by applying the brakes in the usual manner-the movement of the said horizontal brake-rod G in the direction to move the upper end of the live brake-lever F toward the dead-lever K-the opposite brake-shoes O 0 would be forced inwardly against the wheels B B, and when released the opposite movement would act to carry the upper retaining and actuating pawl P, pivoted to the upper end of the dead-lever K, inwardly over one of the teeth N on the upper edge of the ratchet L. The lower actuating and retaining pawl R engaging with one of the teeth M on the lower ratchet L would serve as a fulcrum for the purpose of changing the relative position of the upper end of the dead-lever K to the periphery of the wheel B at that end of the truck.

Now when the brake-shoes O 0 become worn away sufficiently the act of applying the brakes as above described would permit the retaining and actuating pawl R to be carried over one of the teeth M on the said lower ratchet L, and thereby effect the adjustment of the brake-shoes to a new position in relation to the wheels, as desired, and thereby produce an automatic slack-adjuster for railway-car trucks in a very efficient manner. It will be observed that the upward end portion of the said dead-lever K moves loosely between the parallel ratchet-bars which serve as guides.

The inward ends of the pawls P and R turn downward a short distance, 'and each one is provided with a short spiral spring S, the opposite end of which has a bearing against the said dead-lever K, so as to insure their action, and the inward ends of the pawls P and R are connected by a short vertical pivoted bar T, as shown, so that by raising the upper pawl P by its handle V both pawls would thereby become released from the teeth of the upper and lower ratchets simultaneously. It will be understood that the said vertical bar T, which connects the short ends of the pawls P and B, should be pivoted thereto at top and bottom or upper and lower ends very loosely, so that either pawl P or R may be raised a limited distance sufficient for the opposite long ends of either pawl to be raised up, so as to pass over a tooth or out of engagement with a tooth on the said upper or lower segmental rack-bar without raising or disengaging the other pawl from a tooth.

Having thus described my invention, I claim Ina slack-adjuster, the dead-leverhaving 

